TAMPA — Andy Pettitte walked off the mound and Mariano Rivera took over, a baton pass that essentially has been on endless loop throughout their entire adult lives.

If the scene needed any more déjà vu qualities, there was Jorge Posada watching the whole thing.

Except this was different. Posada is retired, and Pettitte and Rivera are in the process of trying to show they shouldn’t be, that their fortysomething bodies still have major league vitality in them following serious injuries last year.

“Me and Mo have big expectations,” Pettitte said. “The last thing I want to do is sound cocky, but we both feel if we are healthy, we will be successful.”

Which is why yesterday morning was not just another throwaway vignette from the slow slog that can be spring training. Sure, the batters wore Nos. 98 and 99 in this simulated game. Sure, the stands were empty. Sure, Posada was watching from behind a protective screen just beyond the back of the mound.

But there are no throwaways when the oldest player in the majors (Rivera, 43) and the oldest starter (Pettitte, 40) lift their arms. They know they are way beyond the life expectancy of their careers. Yet even in the twilight there is a same-as-it-ever-was resonance to this camp because of this: Pettitte and Rivera are as important to the Yankees in their 40s as they were in their 20s and 30s.

With 100 or so homers having fled the premises, the Yankees are going to rely more heavily upon their pitching in 2013 than they did in 2012. Which means Pettitte and Rivera are not here as novelty acts or for touches of nostalgia. Pettitte is the No. 3 starter on a team whose rotation begins to get iffy with Phil Hughes in the No. 4 slot. And Rivera is the closer for a team that lost its bullpen safety net, Rafael Soriano, to the Nationals.

“We both know we are older,” Pettitte said. “But I also know I wouldn’t have come back if I didn’t believe I could perform at a high level and help us win. And I know Mo feels the same exact way.”

Nevertheless, even if they are holding themselves to the same mound standards, Pettitte and Rivera have made concessions to their ages.

Pettitte fractured his ankle last June 27 and missed three months, but gained some wisdom. Unable to return to heavy-duty workouts and risk setbacks that would cost him late September and the playoffs, Pettitte was pleasantly shocked to see how well he pitched without them.

So he has decided to severely curtail what had been his familiar early-morning pre-team boot camps on the backfields. He smiled when he reported how good his body feels without the self-induced misery.

“It has really been a mental battle for me because I have always felt I needed to do more to be effective on the mound,” Pettitte said.

Thus, yesterday provided another symbol that less can be more. Pettitte’s sinker induced grounders from non-roster invites Rob Segedin and Kyle Roller. When Franicsco Cervelli moved inside and outside, the ball found his mitt. “Same guy,” Cervelli said.

And what better news could there be for the Yanks than that Pettitte, 40, is the same guy? Well, that the guy who followed on the mound at 9:30 a.m. under a strong sun also was the same.

Yesterday was significant to Rivera as the first time since last April 30 he had faced batters. Rivera, who tore up his right knee last May 3, delivered 20 pitches with familiar fluidity, athleticism and command.

He threw about eight vintage cutters. One made Roller look like so many lefty hitters before him, beginning a swing at what he thought he saw and then awkwardly trying to hold up as the ball veered and disappeared under his hands.

“That was nasty,” Posada said from behind the screen.

Rivera, 43, is now on a program not that foreign from those of his recent past, when he limited his spring exposure to preserve himself for the regular season. He will not appear in the early exhibition games and probably will not even throw 10 total innings.

So what you will get mainly are snapshots like the one yesterday, when the winningest handoff in major league history — Pettitte to Rivera — looked just fine on a sunny Tampa morning. They already have combined to earn a win and save, respectively, in the same game a record 68 times. And considering how important they remain to the Yankees, the hope around here is: 68 and counting.